Apparatus for performing uplink synchronization in multiple component carrier system and method therefor

Abstract

There are provided an apparatus for performing uplink synchronization in a multiple component carrier system and a method thereof. The method includes determining whether a timing advance value for adjusting uplink timing of a secondary serving cell is valid, entering a transmission holding mode in which the secondary serving cell holds uplink transmission, and determining a releasing condition of releasing the transmission holding mode is satisfied. The timing advance value is secured and the validity of the timing advance value is determined so that it is possible to prevent uplink interference from being generated due to a difference in timing advance values and to prevent capability from deteriorating due to the uplink interference.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority benefit of Korean Patent Application No. 10-2011-0108887, filed on Oct. 24, 2011 and Korean Patent Application No. 10-2012-0102771, filed on Sep. 17, 2012 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to wireless communications, and more particularly, to an apparatus for performing uplink synchronization in a multiple component carrier system and a method thereof.[0004]2. Description of the Related Art[0005]In a common wireless communication system, although bandwidth of an uplink is different from bandwidth of a downlink, only one carrier is mainly considered. A third generation partnership project (3GPP) long term evolution (LTE) is based on a single carrier so that only one carrier forms the uplink and the downlink and that the bandwidth of the uplink...

AI Technical Summary

Benefits of technology

The present invention provides an apparatus and method for performing uplink synchronization in a multiple component carrier system. The invention allows for the determination of validity of a timing alignment value and the release of a transmission holding mode based on the activation or deactivation of a secondary serving cell. The invention also includes a method for measuring downlink timing values and determining the absolute value of a difference between them to determine the validity of a timing advance value. The invention further provides a method for transmitting an uplink signal from a secondary serving cell to the base station based on the timing advance value when the releasing condition is satisfied. The technical effects of the invention include improved synchronization and efficiency in uplink data transmission in a multiple component carrier system.

Problems solved by technology

In the contention based random access procedure, since the UE uses an arbitrarily selected random access preamble, there is probability of contention.

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